It has been shown that defects, such as the presence of faults, discharges, etc., lead to catastrophic failure of power equipment, including medium voltage power cables, switchgears, distribution blocks, electric motors, transformers, etc. One particularly type of defect that causes an abnormal amount of power equipment failure relates to internal discharges, known as partial discharge (PD). As generally known in the art, partial discharge can occurs within an insulation medium, such as the insulation layer of a medium voltage power cable, an insulation component, e.g., bushing, etc., of a transformer, switchgear, etc. In time, partial discharge, left unattended, may significantly deteriorate the insulation medium along with a combination of other factors such as thermal cycling, mechanical fatigue, embrittlement, and moisture ingression. This may lead to a high concentration of electrical stress at the particular location and ultimately voltage breakdown through the insulation medium. Should this occur during a critical period, such as during a peak load for a utility or a critical manufacturing process for a manufacturing concern, the repercussions in terms of financial losses and customer inconveniences can be quite severe.
As stated above, users of expensive medium or high voltage electrical equipment (e.g., medium voltage power cables, switchgears, transformers, electrical motors, generators, etc.) incur extraordinary expenses when power equipment unexpectedly fails. Scheduled maintenance plans are one approach to combat this ongoing problem. However, scheduled maintenance plans cause users to incur unnecessary costs when equipment is found to be functioning satisfactorily after the scheduled maintenance. Therefore, diagnostic systems have been developed that have the ability to predict failures in medium voltage power cable, switchgears, transformers, etc., and thus, enables the equipment user to utilize condition-based maintenance techniques to avert such unexpected failures and associated high costs. Some diagnostic systems attempt to identify any defect that would result in a system failure and predict the time required for these defects to induce the failure in one or more components of the system.